Hawker Siddeley was a group of British manufacturing companies engaged in aircraft production. Hawker Siddeley combined the legacies of several British aircraft manufacturers, emerging through a series of mergers and acquisitions as one of only two such major British companies in the 1960s. In 1977, Hawker Siddeley became a founding component of the nationalised British Aerospace (BAe). Hawker Siddeley also operated in other industrial markets, such as locomotive building (through its ownership of Brush Traction) and diesel engine manufacture (through its ownership of Lister Petter). The company was once a constituent of the FTSE 100 Index.
Hawker Siddeley Aircraft was formed in 1935 as a result of the purchase by Hawker Aircraft of the companies of J. D. Siddeley, the automotive and engine builder Armstrong Siddeley and the aircraft manufacturer Armstrong Whitworth Aircraft. At this time, Hawker Siddeley also acquired A.V. Roe & Company (Avro), Gloster Aircraft Company (Gloster) and Air Training Services. The constituent companies continued to produce their own aircraft designs under their own name as well as sharing manufacturing work throughout the group.
During the Second World War, Hawker Siddeley was one of the United Kingdom's most important aviation concerns, producing numerous designs including the famous Hawker Hurricane fighter plane that, along with the Supermarine Spitfire, was Britain's front-line defence in the Battle of Britain. During this campaign, Hurricanes outnumbered all other British fighters combined in service, and were responsible for shooting down 55 per cent of all enemy aircraft destroyed.
In 1945, Hawker Siddeley purchased Victory Aircraft of Malton, Ontario, Canada from the Canadian government, renaming the company A.V. Roe Canada, commonly known as Avro Canada, initially a wholly owned subsidiary of Hawker Siddeley. Avro Canada underwent a major expansion through aircraft development and acquisition of aircraft engine, mining, steel, railway rolling stock, computers, electronics, and other businesses to become, by 1958, Canada's third largest company directly employing over 14,000 people and providing 45% of the parent company's revenues.